Hi Daan, Kester makes some claims about reducing voiding. Their R560 water soluble paste has a statement that it reduces voiding from 25% to less than 10%. Their R562 water soluble formula has a statement that voids will be reduced to less than 3%. I'll send you the *.PDF datasheets for both. I've never done any tests to verify that, so maybe you'll find out if it's true! -Steve Gregory-